Blender VSE Renders audio/video out of sync
I edit videos almost daily with Blender, but I never faced your issue.

I highly recommend giving Blender Velvets a try. The Velvet Revolver add-on allows you to transcode all of your footage to an editing-friendly video format, using FFMPEG. It also makes editing in Blender much more efficient, but that's another story! I recommend that you use the MJPEG format with Revolver, prores is way too heavy.



Most video editing software out there only support a limited set of codecs for technical reasons, and you can have issues editing with videos that use the h264 codec. The lovely compression it provides comes at a cost: your video's frames are not available individually in the movie file, making it hard to decode, hard to split frames... so your issue is most likely due to that.

I hope it'll help, and if it doesn't, could you upload a blender file with a sample of the incriminated footage?

Kind regards,
Nathan.